Got to share about this one very recently and I'm very happy to get to share it with you guys here!!
This seamless texture, consists of 6 textures to create this effect. 4 noise textures and 2 gradient textures to blend the noise textures when they're in the right positions for tiling,
Now, you can't make it tileable, if you don't blend the textures somewhere, or you would have simply shifted the seam. So they do have blending areas, but in the middle of the UV square, like cross hairs. Think of Gimp's Mapping feature. Like that, except, in the middle. I added a feature to distort this seam and make it vanish even more, so yay for that! :D
To make that seam vanish seamlessly (hehe), you duplicate the texture for itself using the color feature (see example image). Don't go too far with the intensity though. It's too much to even go beyond 0.4 tbh. Limit yourself to the default for the best result. For ease of use, I added an additional group with all those things setup called Global. The other one that is seamless, but use a gradient only, is called Single.
Adding these to your scene is very easy - you go FIle, Append, NodeTree and select the applicable setup you need: - Seamless Procedural Noise UV - Global - Contains two single nodes to distort the gradient texture for better seamlessness in animation - Seamless Procedural Noise UV - Single - Contains the seamless texture with gardient blending only
You can enter the Single's setup to adjust the blend area - it is clearly marked where you can edit the Ramps.
And that's all there is to it! Have fun!!
NOTE: It can be quite resource intensive on older computers. Baking is a fantastic option in your case.